/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved  	*/

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved. The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#include "refer..c"

static int *coord = 0;
int hh[50];
extern int *hfreq, hfrflg;
extern int prfreqs;
union ptr {
	unsigned *a;
	long *b;
};

extern int hash();
extern void shell();
extern void *zalloc();

static long getl(FILE *);
static int hcomp(int, int);
static void hexch(int, int);

int
doquery(long *hpt, int nhash, FILE *fb, int nitem,
	    char *qitem[], unsigned *mptr)
{
	long k;
	union ptr prevdrop, master;
	int nf = 0, best = 0, nterm = 0, i, g, j;
	int *prevcoord;
	long lp;
	extern int lmaster, colevel, reached;
	extern int iflong;

	if (iflong) {
		master.b = (long *)mptr;
	} else {
		master.a = mptr;
	}

#if D1
	fprintf(stderr, "entering doquery nitem %d\n", nitem);
	fprintf(stderr, "first few hashes are %ld %ld %ld %ld %ld\n",
	    hpt[0], hpt[1], hpt[2], hpt[3], hpt[4]);
	fprintf(stderr, "and frequencies are  %d %d %d %d %d\n",
	    hfreq[0], hfreq[1], hfreq[2], hfreq[3], hfreq[4]);
#endif
	assert(lmaster > 0);
	if (coord == 0)
		coord = (int *)zalloc(lmaster, sizeof (lmaster));
	if (colevel > 0) {
		if (iflong)
			prevdrop.b = (long *)zalloc(lmaster, sizeof (long));
		else
			prevdrop.a = (unsigned *)zalloc(lmaster, sizeof (int));
		prevcoord = (int *)zalloc(lmaster, sizeof (lmaster));
	} else {
		prevdrop.a = master.a;
		prevcoord = coord;
	}
#if D1
	fprintf(stderr, "nitem %d\n", nitem);
#endif
	for (i = 0; i < nitem; i++) {
		hh[i] = hash(qitem[i])%nhash;
#if D1
		fprintf(stderr, "query wd X%sX has hash %d\n", qitem[i], hh[i]);
#endif
	}
#if D1
	fprintf(stderr, "past that loop nhash %d hpt is %lo\n", nhash, hpt);
#endif
	if (prfreqs)
		for (i = 0; i < nitem; i++)
			fprintf(stderr, "item %s hash %d hfreq %d\n",
			    qitem[i], hh[i], hfreq[hh[i]]);
	/* if possible, sort query into decreasing frequency of hashes */
	if (hfrflg)
		shell(nitem, hcomp, hexch);
#if D1
	for (i = 0; i < nitem; i++)
		fprintf(stderr, "item hash %d frq %d\n", hh[i], hfreq[hh[i]]);
#endif
	lp = hpt [hh[0]];
#if D1
	fprintf(stderr, "first item hash %d lp %ld 0%lo\n", hh[0], lp, lp);
#endif
	assert(fb != NULL);
	assert(fseek(fb, lp, 0) != -1);
	for (i = 0; i < lmaster; i++) {
		if (iflong)
			master.b[i] = getl(fb);
		else
			master.a[i] = getw(fb);
		coord[i] = 1;
#if D2
		if (iflong)
			fprintf(stderr, "master has %ld\n", (master.b[i]));
		else
			fprintf(stderr, "master has %d\n", (master.a[i]));
#endif
		assert(i < lmaster);
		if (iflong) {
			if (master.b[i] == -1L) break;
		} else {
			if (master.a[i] == -1) break;
		}
	}
	nf = i;
	for (nterm = 1; nterm < nitem; nterm++) {
#ifdef D1
		fprintf(stderr, "item %d, hash %d\n", nterm, hh[nterm]);
#endif
		if (colevel > 0) {
			for (j = 0; j < nf; j++) {
				if (iflong)
					prevdrop.b[j] = master.b[j];
				else
					prevdrop.a[j] = master.a[j];
				prevcoord[j] = coord[j];
			}
		}
		lp = hpt[hh[nterm]];
		assert(fseek(fb, lp, 0) != -1);
#if D1
		fprintf(stderr, "item %d hash %d seek to %ld\n",
		    nterm, hh[nterm], lp);
#endif
		g = j = 0;
		while (1) {
			if (iflong)
				k = getl(fb);
			else
				k = getw(fb);
			if (k == -1) break;
#if D2
			fprintf(stderr, "next term finds %ld\n", k);
#endif
#if D3
			if (iflong)
				fprintf(stderr,
				    "bfwh j %d nf %d master %ld k %ld\n",
				    j, nf, prevdrop.b[j], (long)(k));
			else
				fprintf(stderr,
				    "bfwh j %d nf %d master %ld k %ld\n",
				    j, nf, prevdrop.a[j], (long)(k));
#endif
			while (j < nf &&
			    (iflong ? prevdrop.b[j] : prevdrop.a[j]) < k) {
#if D3
				if (iflong)
					fprintf(stderr, "j %d nf %d prevdrop "
					    "%ld prevcoord %d colevel %d nterm "
					    "%d k %ld\n", j, nf, prevdrop.b[j],
					    prevcoord[j], colevel, nterm,
					    (long)(k));
				else
					fprintf(stderr, "j %d nf %d prevdrop "
					    "%ld prevcoord %d colevel %d nterm "
					    "%d k %ld\n", j, nf, prevdrop.a[j],
					    prevcoord[j], colevel, nterm,
					    (long)(k));
#endif
				if (prevcoord[j] + colevel <= nterm)
					j++;
				else {
					assert(g < lmaster);
					if (iflong)
						master.b[g] = prevdrop.b[j];
					else
						master.a[g] = prevdrop.a[j];
					coord[g++] = prevcoord[j++];
#if D1
					if (iflong)
						fprintf(stderr, " not skip g "
						    "%d doc %d coord %d note "
						    "%d\n", g, master.b[g-1],
						    coord[g-1], master.b[j-1]);
					else
						fprintf(stderr, " not skip g "
						    "%d doc %ld coord %d nterm "
						    "%d\n", g, master.a[g-1],
						    coord[g-1], nterm);
#endif
					continue;
				}
			}
			if (colevel == 0 && j >= nf) break;
			if (j < nf &&
			    (iflong ? prevdrop.b[j] : prevdrop.a[j]) == k) {
				if (iflong)
					master.b[g] = k;
				else
					master.a[g] = k;
				coord[g++] = prevcoord[j++]+1;
#if D1
				if (iflong)
					fprintf(stderr, " at g %d item %ld "
					    "coord %d note %ld\n", g,
					    master.b[g-1], coord[g-1],
					    master.b[j-1]);
				else
					fprintf(stderr, " at g %d item %d "
					    "coord %d note %d\n", g,
					    master.a[g-1], coord[g-1],
					    master.a[j-1]);
#endif
			} else
				if (colevel >= nterm) {
					if (iflong)
						master.b[g] = k;
					else
						master.a[g] = k;
					coord[g++] = 1;
				}
		}
#if D1
		fprintf(stderr, "now have %d items\n", g);
#endif
		if (colevel > 0)
			for (; j < nf; j++)
				if ((iflong ? prevdrop.b[j] : prevdrop.a[j]) +
				    colevel > nterm) {
					assert(g < lmaster);
					if (iflong)
						master.b[g] = prevdrop.b[j];
					else
						master.a[g] = prevdrop.a[j];
					coord[g++] = prevcoord[j];
#if D3
					if (iflong)
						fprintf(stderr, "copied over "
						    "%ld coord %d\n",
						    master.b[g-1], coord[g-1]);
					else
						fprintf(stderr, "copied over "
						    "%d coord %d\n",
						    master.a[g-1], coord[g-1]);
#endif
				}
		nf = g;
	}
	if (colevel > 0) {
		best = 0;
		for (j = 0; j < nf; j++)
			if (coord[j] > best) best = coord[j];
#if D1
		fprintf(stderr, "colevel %d best %d\n", colevel, best);
#endif
		reached = best;
		for (g = j = 0; j < nf; j++)
			if (coord[j] == best) {
				if (iflong)
					master.b[g++] = master.b[j];
				else
					master.a[g++] = master.a[j];
			}
		nf = g;
#if D1
		fprintf(stderr, "yet got %d\n", nf);
#endif
	}
#ifdef D1
	fprintf(stderr, " returning with %d\n", nf);
#endif
	if (colevel) {
		free(prevdrop, lmaster, iflong ? sizeof (long): sizeof (int));
		free(prevcoord, lmaster, sizeof (lmaster));
	}
#if D3
	for (g = 0; g < nf; g++)
		if (iflong)
			fprintf(stderr, ":%ld\n", master.b[g]);
		else
			fprintf(stderr, ":%d\n", master.a[g]);
#endif
	return (nf);
}

static long
getl(FILE *fb)
{
	return (getw(fb));
}

static int
hcomp(int n1, int n2)
{
	return (hfreq[hh[n1]] <= hfreq[hh[n2]]);
}

static void
hexch(int n1, int n2)
{
	int t;
	t = hh[n1];
	hh[n1] = hh[n2];
	hh[n2] = t;
}
